The present invention relates to a photographic method and apparatus, and more particularly to a photographic method, film pack and camera wherein film units for the production of individual photographs are constituted by first sheets each comprising a photosensitive layer and an equal number of second sheets associated with developing solution containers which, when initially loaded in a camera, are held separate from one another, successive photographs being produced by exposure of successive first sheets, which are then transferred into contact with successive second sheets, so as to cover the photosensitive layers of first sheets with second sheets in facing contact with each other, thereby to form successive assembled independent semi-film units, which are placed apart from and physically separated from first sheets, and, in turn, subsequently removed from the camera while being simultaneously processed with developing solution of containers to produce complete film units.
There are known conventionally, various photographic methods and apparatus, which are frequently referred to as `auto-processing` and `auto-process cameras`, whereby development of an exposed film is effected within a camera, thus permitting a photographer to obtain an image of an object photographed in a very short time after the shot is taken, without having to go to a separate establishment for film development.
According to a known auto-processing, development as well as exposure of a film is carried out inside a camera, and a film is provided not in a continuous roll but as a series of individual film units, which may or may not be linked to one another, and a plurality of which are usually held in a pack or similar container which is loadable in a camera, each film unit being for the production of one photograph, and comprising at least a photosensitive layer which is exposable to produce a negative image of an object, a transfer layer, which is in immediate or close juxtaposition to the photosensitive layer, and onto which a viewable image corresponding to the negative image of the photosensitive layer may be diffused and transferred under the action of a processing solution spread between the layers, and a pod, which contains a requisite solution for effecting this diffusion and transfer. In an auto-process, for each photograph, the photosensitive layer of a film unit is exposed, and this film unit is then moved out of the pack, the other film units remaining in the pack, and is passed through pressure means such as rolls, which are provided in a camera, and cause the processing solution pod of the film unit to be broken open and the solution to be spread between the film layers, while at the same time pressing the layers together, and forwarding the film unit to the exterior of the camera, these steps taking place in a short time. In principle, employment of an auto-process camera as opposed to for example, a camera associated with tank-developed roll film, presents a main advantage in that a photographer obtains a photographic print almost immediately after exposure of each film unit, without the trouble and expense of going to a separate establishment for development of film. However, while representing a definite technical advance in some respects, conventional auto-process cameras still have drawbacks, either with regard to ease of handling, or to quality of prints obtained.
For example, one representative type of conventional auto-process camera exploys film units, which each comprise at least a photosensitive sheet, a transfer image sheet, and a pod containing processing solution, and which are provided in a cassette or pack which is loadable in the camera, the film units in the pack being linked in a continuous series by comparatively thin sheets of tape or paper termed leaders, which are lightproof, and which are normally doubled between successive film units, or behind successive photosensitive sheets, there also being a leader doubled in front of the foremost film unit prior to loading of the pack into the camera. With this camera, for each photograph taken, the leader in front of a film unit is drawn out a certain amount to uncover the film unit, the film unit is exposed, and then the leader is drawn out further in order to pull the exposed film unit first through processing rolls provided in the camera, and then out of the camera, leaders and film units usually being connected in such a manner that drawing-out of an exposed film unit from the camera causes the next film unit in the pack to be uncovered. This drawing-out of successive leaders, and so of successive film units must be effected by the photographer, which apart from being troublesome, also tends to be unsatisfactory, since it is evidently impossible to guarantee that all exposed film units will be drawn through the processing rolls at the same rate, and processing of different film units, or even of different portions of one and the same film unit may fail to be uniform. Even supposing that film unit processing is susceptible of being rendered more uniform, for example by the provision of extra drive means associated with the processing rolls, this type of camera still has a particular disadvantage in that initial loading of film packs thereinto is fastidious and somewhat difficult, since before the camera can function the photographer must thread a leader between the processing rolls and through a passage to the exterior of the camera. Also, since, during use of the camera, there is always a leader extending from the film pack loaded therein, through the processing rolls, to the exterior of the camera, as long as there are still film units remaining in the pack, it is very difficult to unload the pack without risk of damage to camera parts. This is inconvenient when, for example, there are only one or two unexposed film units left in the camera, and a photographer anticipates taking 6 - 8 shots in rapid succession, and so wishes to load the camera ready with a pack having a full complement of film units, or when a photographer wishes to immediately employ film units having a sensitivity to light, or other characteristics, different from those of film units currently loaded in the camera. Further disadvantages of this type of camera are that, in order to obtain useable prints, a photographer is usually obliged to separate the photosensitive sheets and transfer sheets of processed film units a certain time after extraction of the film units from the camera, and that a processed film unit is always accompanied by a leader which must be detached, in addition to this, either a photographer has the trouble of disposing of the leaders, and possibly of a photosensitive sheets also, or these elements are simply discarded and become litter, which is obviously undesirable.
In another representative type of conventional auto-process camera, film units are provided as a set of unconnected units, termed monosheets, which are each an individual combination of at least a photosensitive layer for production of a negative image, a transfer layer for production of a corresponding useable image, and a processing solution pod, and which are exposed, processed and moved out of the camera automatically, the only action required of a photographer being depression of the camera shutter button, and each successive exposed monosheet being moved independently of other monosheets in the camera, and brought out of the camera unaccompanied by leaders or other unrequired elements. This type of camera has the advantages that loading or unloading of film packs thereinto or therefrom is comparatively straightforward, that actions required of a photographer are minimum, and that there is not objectionable litter. However, this type of auto-process camera has a principal disadvantage in that, since the monosheets associated therewith are each a complete unit comprising all necessary elements for production of a photograph, different portions of each monosheet have different thicknesses, in particular the processing solution pod usually being thicker than the rest of the monosheet, with the result that when a plurality of monosheets are held in a pack, if the foremost monosheet is to be in suitably flat alignment for correct exposure, it is necessary to apply comparatively high forward or feed pressure on the monosheets, and even then it is difficult to guarantee suitable flatness of film units, and hence production of satisfactorily sharp images. Also, because of the comparatively strong pressure applied on monosheets, qualities of photosensitive layers thereof may be impaired if the monosheets are stored for a long time. Another disadvantage is that since in producing a photograph with a monosheet employed in this type of camera light passes through the transfer layer to produce an image on the photosensitive layer, and this image is subsequently diffused back to the transfer layer, the camera lens system must include a mirror or mirrors if a print carrying a correct image is to be obtained.
Accordingly, the essential object of the present invention is to provide a photographic method and apparatus which eliminates the disadvantages inherent in conventional auto-processing methods and also presents other novel advantages.
In more detail, objects of the present invention are to provide a photographic method and apparatus enjoyable great advantages such that;
a plurality of first sheets each comprising a photosensitive layer may merely be packed together, in disregard to the developing solution containers, and easily maintained in good flat alignment, whereby successive last sheets may be exposed without risk of formation of ghost images,
first sheets having photosensitive layers are stored separately and out of contact with second sheets prior to use, whereby the risk of deterioration of film quality during long storage is minimized;
each successive first sheet is transferred, after exposure thereof, to a second sheet, which is located in another part of the camera, which covers and protects the photosensitive layer of the first sheet, and with which there is associated a container of chemical developing solution which my be spread between the first and second sheets, whereby there is formed a semi-film unit, which is independent of other first sheets and second sheets,
semi-film units being processable to give immediately useable prints in cameras wherein light for exposure of film is directed thereonto by normal geometrical optical system to form positive images, or wherein light is directed onto film by an optical system including a mirror or mirrors, to revert light rays and produce mirror images;
each independent semi-film unit is transferred to the exterior of the camera without attendant unrequired material such as leaders, and processed and developed during this transfer to form a complete film unit, whereby film is automatically processed immediately after exposure thereof, and a photographer may take shots in rapid succession;
a complete film unit which has been removed from a camera comprising a negative film portion, which is protected, but is easily separable from the positive print portion, and may be subsequently employed to produce further copies of a photograph.
It is another object of the present invention to provide a film pack wherein photosensitive sheet portion of semi-film units may be held separately from other film unit portions, and are easily held in a correct alignment for exposure, and wherefrom successive semi-film units, which are formed by successive exposed photosensitive sheets transferred into successive envelopes providing lightproof protection therefor, may be removed and directed outside of the camera, without leaders being necessary, each semi-film unit being removed completely independently of other film units.
The corresponding envelope also may have various structures, to match different structures of the photosensitive sheet, and meet various purposes. For example, the envelope may be simply a completely opaque cover providing lightproof protection for a photosensitive sheet, or, inside the opening of the envelope, there may be provided a container holding processing solution for effecting diffusion-transfer of an image in an auto-process photosensitive sheet, or one side of the envelope may constitute a transfer sheet, onto which an image may be diffused and transferred from a photosensitive sheet inserted in the envelope.
It is a further object of the invention to provide a camera which permits separate storing of one or more first sheets each comprising a photosensitive layer exposable to form a negative image, and of an equal number of second sheets each associable with a processing solution pod and comprising a lightproof layer and, optionally, a layer for formation of an image by diffusion-transfer process, which comprises a lens and shutter means permitting exposure of successive first sheets, and which, upon exposure of each successive first sheet effects a sequence of actions comprising moving the exposed first sheet into correctly aligned assembly with a corresponding second sheet, to constitute a semi-film unit that is unattached to elements of other film units in the camera, and then moving this independent, semi-film unit through processing means provided in the camera, and directing the film unit to the exterior of the camera.
It is another object of the invention to provide a camera comprising time-, or switch-controlled means for effecting the abovedescribed actions in the required sequence.
It is a still further object of the invention to provide a camera permitting film unit portions for formation of negative images to be initially stored separately from other film unit portions, whereby film unit negative image portions may be constructed to each have an even cross-section, and so be easily held in an alignment ensuring correct exposure thereof.
It is yet another object of the invention to provide a camera which is not limited to association with only one type of film, but is associable with various types of auto-process film unit or of tank-developed film unit.
It is still further object of the invention to provide a camera which permits a varied camera construction and in which a lens system may include or may dispense with a mirror or mirrors, according to different requirements and structural combinations of film units employed.
In accomplishing these and other objects, there is provided, according to the present invention, a photographic method and means wherein each semi-film unit to be assembled for production of a single photograph, is constituted by a first sheet, and a second sheet, which is connectable to the first sheet, through a leader, but is maintained physically separate therefrom prior to a photograph being taken, and is associated with a breakable container holding a processing solution, the first sheet and second sheet are brought together to form a semi-film unit only after exposure of the first sheet to produce a negative image thereon. Subsequently, this semi-film unit is removed from the camera while being simultaneously processed to form a complete film unit. Each semi-film unit as a whole comprises at least for the formation of a negative image of a desired object, a layer on which a positive image of the object may be formed by diffusion-transfer from the negative layer, under the influence of the processing solution, a support layer, and a lightproof protective layer. Other layers, such as a spacer, may also be included, to meet various purposes. The negative image layer is always included in the first sheet, the positive image layer and lightproof protective layer may be included in the first sheet or in the second sheet, and a support layer may be included in either the first sheet or the second sheets, or both.
According to the present invention, there is provided a camera having a known lens system and shutter means, and providing accommodation for a pack containing a plurality of semi-film units, each of which is constituted by a first sheet, which is initially held in a forward portion of the pack, and a second sheet, which is held in a rear portion of the pack, is initially separate from the first sheet, and is provided either as a single sheet, or as a main second sheet and a subsidiary second sheet which are initially in partial attachment to one another and constitute a subsequently completely sealable envelope for containment of the first sheet. If it is required to use the camera of the invention for auto-processing, each semi-film unit comprises a photosensitive layer, which is exposable to form a negative image, and is always included in the first sheet of the film unit, at least one lightproof layer, which is associable either with the first sheet or with the second sheet, or with both, an image transfer layer, which is included either in the first sheet or in the second sheet, and a processing solution pod, which is associated with the second sheet.
Alternatively, the first sheet may be simply a film which is developable in a tank-process, and the second sheet constitute a lightproof envelope which may contain the first sheet, and is sealable to provide complete lightproof protection therefore.
In taking a photograph, the camera shutter means is actuated to expose the photosensitive layer in the first sheet or a semi-film unit, and then a means provided in the camera, which acts either directly on the exposed first sheet, or actuates a first sheet shift means provided in the loaded pack containing the film units, moves the exposed first sheet into contact with, or into the envelope constituted by a corresponding second sheet, this first sheet and second sheet constituting a independent semi-film unit which is ready for processing, and which, although contacted by the second sheet of another film unit, is in no way attached to other film unit elements, and may be moved independently of other film units, and unaccompanied by any unrequired elements which must be subsequently detached and disposed of. This semi-film unit is then moved out of the pack by a means provided in the camera, and into engagement with processing means, which also are provided in the camera, and which serve to bond the first sheet and second sheet together, or to seal the envelope constituted by the second sheet, and to cause processing from the pod associated with the second sheet to be spread through the film unit, or, if the first sheet is a tank-developed film, simply to seal the envelope constituted by the second sheet, while simultaneously forwarding the film unit to the exterior of the camera, where it is made available to the photographer.
Thus, a plurality of semi-film units, when initially loaded into a camera of the invention, are constituted by a certain number of first sheets held in a camera first location, wherein the first sheets may be exposed to light directed into the camera by the camera lens system, and an equal number of second sheets held separately from the first sheets in a second location, and as successive shots are taken, successive first sheets are exposed, then transferred from the first location to the second location and therein brought into association with successive second sheets to constitute successive independent film units, which are then moved out of the camera, while simultaneously being processed or not, according to the type of film.
One appreciable advantage offered by the invention is that by making it possible for different portions of film units to be initially stored separately from one another, those portions of a film unit which are of uneven thickness or shape, e.g., the processing solution pod, may be associated with the film unit second sheet in the camera second location, i.e., away from the first location where exposure takes place, and first sheet construction may be made flat, even if the first sheet comprises a plurality of layers, and the first sheet may therefore be easily and accurately held in an alignment ensuring correct exposure. For each film unit, therefore, the main function of the second sheet is to provide a support or envelope for an exposed first sheet, and to carry or be associated with any film unit uneven portions such as the processing solution pod, in addition to which the second sheet may or may not include active portions of a semi-film unit.
For example, a suitable film unit construction when the optical system of the camera comprises a mirror or mirrors for image reversal is that the first sheet comprises a transparent support layer, a photosensitive layer, which is coated on one side of the support layer, and a lightproof, protective layer which is coated on, or incorporated in, and backs, the photosensitive layer, comprises, for example, a hydrophilic colloid containing a light-absorbent substance, and which although lightproof is permeable to a processing solution, the function of this lightproof layer being to prevent fogging of other first sheets loaded to the rear of the first sheet being exposed. The first sheet is initially positioned with the transparent support layer there of foremost, thus permitting exposure of the photosensitive layer and formation of an image therein. The corresponding second sheet, which as noted earlier is held in the second location and is physically separate from the first sheet prior to a photograph being taken is associated with a pod holding processing solution, and is constituted by a main second sheet comprising a transparent support layer backed by a positive image layer on which a photographic image may be formed by diffusion-transfer process, and a subsidiary second sheet, which is made of a lightproof material, and which, prior to a photograph being taken is in partial attachment, for example, along three edges, to the main second sheet, whereby the main second sheet and subsidiary second sheet together constitute an envelope in which the first sheet is containable, the second sheet transparent support layer being foremost and the subsidiary second sheet being rearmost in the normal loaded position of the second sheet. After exposure, the first sheet is moved out of the first location, caused to make a U-turn and to flip over, whereby the lightproof layer thereof is brought foremost, and the first sheet is then inserted into the envelope constituted by the second sheet, the first sheet protective layer thus being brought into contact with the second sheet positive image layer, and the first sheet transparent support layer being brought into contact with the lightproof subsidiary second sheet, i.e., the first sheet photosensitive layer carrying a negative image is now contained between two lightproof layers. Subsequently, this single film unit constituted by the first sheet and second sheet is moved from the camera, and during this removal the processing solution pod is broken open by means provided in the camera, whereby an image is diffused and transferred to the second sheet positive image layer, and the main second sheet and subsidiary second sheet are completely bonded together, there thus being made available outside the camera a positive image of the object photographed which is viewable through the transparent support layer of the second sheet, and a negative image of the object, which is protected between two lightproof layers, and which may, if subsequently required, be separated from the positive print, and used to obtain further copies of the same photograph. In association with this and other types of film unit there is provided means for moving successive first sheets into a position for exposure, and successive second sheets into a position for receiving exposed first sheets, such means being conveniently constituted by, for example, a single spring means acting in opposite directions, which press forwardly on the first sheets and rearwardly on the second sheets.
In another type of semi-film unit construction which may be suitably employed when the camera optical system includes a mirror or mirrors, the first sheet is constituted by a photosensitive layer for the formation of a negative image coated on the forward side of a support layer, which is permeable to processing solution and contains a light-absorbent substance, for example, polyethylene terephthalate film-base containing carbon black, and the second sheet is as described above, i.e., it is associated with a processing solution pod, and includes a main second sheet, which comprises a layer for formation of a positive image coated on the rear side of a transparent support layer, and constitutes an envelope together with a rearmost, lightproof subsidiary second sheet. With this film construction also, after exposure of the first sheet, the first sheet is moved out of the first location, reversed, and moved into the envelope constituted by the second sheet in the second location, the photosensitive layer and light-absorbent support layer of the first sheet thus being brought into juxtaposition with the lightproof subsidiary second sheet and the main second sheet positive image layer, respectively, after which this independent film unit constituted by the first sheet and second sheet is moved out of the camera, while being simultaneously processed, as described above.
In another suitable construction of a semi-film unit employable in a camera according to the invention, the first sheet comprises five layers. In the initial loaded position of the first sheet these layers, going from front to rear, are a photosensitive layer, a lightproof layer containing a substance which is light-absorbent and permeable to processing solution, a layer for reflection of white light, which also is permeable to processing solution, a layer for formation of a positive image, and a transparent support layer. The corresponding second sheet is simply a support sheet, which may be lightproof, is bondable to the first sheet, and has attached a container holding processing solution. When the foremost, photosensitive layer of the first sheet has been exposed, the first sheet is turned over, and transferred to the second location and brought into flat contact with the second sheet, the first sheet photosensitive layer being in immediate juxtaposition to the second sheet, and the first sheet transparent support layer now being foremost. Next, the first and second sheet are moved out of the camera as a single film unit, and during this movement the processing solution pod attached to the second sheet is broken open by rolls, or similar pressure means provided in the camera, which cause the processing solution to be spread throughout the first sheet, whereby an image of the photographed object is produced by diffusion-transfer process on the positive image layer of the first sheet, and is viewable through the first sheet transparent support layer, and which also cause the first and second sheets to be bonded together.
Another type of film that may be employed is ordinary colour, or black and white film developable in a tank-process, in which case the first sheet may comprise, for example, a layer for reflection of white light and a silver halide emulsion layer successively coated on a lightproof support, and the second sheet, or the first sheet may not include a lightproof layer, and the second sheet comprise a main second sheet and a subsidiary second sheet both made of a lightproof material and together constituting an envelope for containment of the first sheet.
Needless to say, the actual physical or chemical compositions of different layers of a first sheet or second sheet of a film unit, or of a processing solution, may be any suitable known compositions to meet different requirements. For example, in the production of black and white photographs in a diffusion-transfer process, the photosensitive layer may be a silver halide emulsion, the positive image layer include a suspension of silver particles to act as nuclei for the development of an image, and the processing solution contains a developing chemical and silver halide solution. In the production of colour photographs by diffusion-transfer process, the photosensitive layer may be a combination of a silver halide emulsion with pigment donor substances for production of different components of a colour image (e.g., a compound for production or promotion of colour elements upon oxidation and reaction of a coupler for production of diffusable colour elements, and a colour developer), the positive image layer may include a medium for fixing colour elements, and the processing solution may be an alkali solution composition including components for promotion of development and colour donor substances.
In order to retain photosensitive sheets and envelopes in their respective positions, regardless of the attitude of the camera in which they are loaded, and to move an exposed photosensitive sheet independently of other photosensitive sheets and position it smoothly and accurately in an envelope positioned to receive the exposed photosensitive sheet, thereby to form a complete film unit, after which it must be possible to move only this film unit accurately from the camera, according to the present invention there is provided a pack which is made of a lightproof material, and the interior of which comprises a first space and a second space. The first space is defined by the inner side of a first wall, in which there is formed an exposure opening, and provides accommodation for a plurality of photosensitive sheets, each of which comprises a photosensitive layer, and which are held in place, and urged towards the pack first wall by a pressure plate. The second space is defined by the inner side of a second wall opposite to the first wall, and provides accommodation for a plurality of envelopes, comprises an opening permitting insertion of a photosensitive sheet thereinto, has at least one side made of a lightproof material, in order to provide lightproof cover for a photosensitive sheet contained therein, the envelopes being held in place, and urged towards the second wall by a pressure means. The pack also comprises a passage section, which is formed at the side of the pack towards which the openings of the envelopes face, and provides communication between the first and second spaces, and a removal opening, which is located in line with an envelope immediately in contact with the second wall. After exposure and formation of a negative image on the photosensitive sheet which is positioned against the pack exposure opening, the exposed photosensitive sheet is moved through the passage section and inserted into the envelope which is currently in immediate contact with the second wall, thereby forming, in the second space, a single film unit, which is independent of the other envelopes.
Corresponding envelopes for containing photosensitive sheets each have an opening permitting insertion of at least one photosensitive sheet and is each able to provide complete lightproof protection for at least one side of a photosensitive sheet contained therein. Each envelope may, for example, have two sides made of a lightproof material, and so constitute a completely opaque cover for a photosensitive sheet, or may have one side made of a lightproof material, while the other side thereof constitutes a layer on which a colour or black and white image may be produced by diffusion-transfer process, and in this case a container which holds processing solution may be attached to the inner side of the transfer image sheet, near the opening of the envelope, whereby each envelope together with an exposed photosensitive sheet may constitute an auto-process film unit.
The pressure plate and pressure means associated with the first space and second space respectively may be constituted a separate spring means, or may be different portions of one and the same spring means, which exerts pressure both on photosensitive sheets and on envelopes, and ensures that the photosensitive sheets and the envelopes are held in position regardless of the attitude of the camera in which the pack is loaded. The passage section providing communication between the pack first and second spaces, and permitting transfer of an exposed photosensitive sheet into an envelope may extend through, or be formed at the inner side of a pack side wall. The passage section may also be constituted by passages which communicate with the first and second spaces and with a passageway formed in a camera, in which case, to transfer an exposed photosensitive sheet into an envelope, the photosensitive sheet is first moved out of the pack, and through the passageway into the camera, and then re-inserted into the pack and directed into the envelope.
Also in this case, if the end of the envelope which an exposed photosensitive sheet first enters when inserted into the envelope is the same end as that which leads when the independent film unit constituted by the photosensitive sheet in the envelope is withdrawn from the pack, the opening between the passage section and the second space can serve as a film unit withdrawal opening, as well as a photosensitive sheet insertion opening. Also, this film unit removal opening must, of course, ensure that, after constitution of each film unit by an exposed photosensitive sheet inserted in an envelope, only one film unit at a time is removed, and it must be ensured that other, unrequired envelopes are not drawn out with a film unit being withdrawn.
As noted above, film units are conveniently stored initially in a pack which is loadable in a camera, and successive first sheets are moved, after exposure thereof, into association with successive second sheets to form successive independent film units for subsequent removal and processing, there being provided spring or similar means for moving each successive first sheet into a position for exposure upon exposure and removal of the preceding first sheet, and for moving each successive second sheet into a position for reception of a first sheet upon removal of the preceding second sheet and first sheet associated therewith. According to the invention, transfer of exposed first sheets to corresponding second sheets may be effected in a manner employing leaders, in which case first sheets are initially linked by leaders, which are provided in the film unit pack and pull successive first sheets to the location of corresponding second sheets, or in a manner in which leaders are not employed, in which case first sheets are unattached to one another, and are transferred to the corresponding second sheets by means provided in the camera and external to the pack. In both modes of transfer the second sheets are unattached to one another, and the first sheets are caused to describe a U-turn while being transferred to the corresponding second sheets.
When leaders are employed, semi-film units are initially contained in a pack which comprises a portion for containment of used leaders and accommodation for a reel or similar means for wind-up of leaders, there being one leader associated with each first sheet. Each leader is fixedly attached at an intermediate point to a slack portion connecting to the leader associated with the next first sheet, and is firmly, but not permanently attached at one end to a first sheet, and passes through an end portion of the pack, along the length of a corresponding second sheet, and also therethrough if the second sheet constitutes an envelope, and then passes through a slit formed at an end of the second sheet, the other end of the leader being taken up on the wind-up reel provided in the pack. The leader slit formed in the second sheet is not wide enough to permit passage of a first sheet, but only of a leader, and, if the second sheet constitute an envelope, it is formed at the closed end of the envelope, or, if the second sheet is a single sheet, it is formed in a turned-back end portion of the second sheet, or in a small block portion provided on one end of the second sheet. When a foremost first sheet is exposed, the leader wind-up means in the pack is actuated by a means provided in the camera, whereby the first sheet is drawn by the leader from the foremost position, guided round one end of the pack, while still remaining in the pack, and then drawn into the envelope, or into contact with the cover constituted by the corresponding second sheet, which is the rearmost second sheet, the slack portion also being wound up during this action. When the first sheet has been drawn into correct alignment with the second sheet, further movement of the first sheet relative to the second sheet is prevented by contact of one end of the first sheet with the sealed or blocking end of the second sheet in which the leader slit is formed. The leader continues to be wound up however, and so is pulled out of attachment with the first sheet and through the leader slit of the second sheet, whereby the first and second sheets remain as an independent semi-film unit which is not attached to, although in contact with, other film unit elements. This stage of wind-up of the leader is detected by a means provided in the camera, which also causes actuation of the leader wind-up means to stop, the leader of the next first sheet now being linked to the leader wind-up means by the slack portion which is connected thereto, and which by now has been completely or almost completely taken up on the leader wind-up means. After this the film unit constituted by the assembled first sheet and second sheet is moved by means provided in the camera through a removal slot formed in the pack, and into contact with processing means as described above, and then out of the camera, via a suitable extractigon passage.
In another embodiment of the invention, first sheets initially loaded in a pack are in contact with one another, but are not attached to one another. After exposure of a foremost first sheet, means provided in the camera move the first sheet out of the pack via a first sheet slit formed at one end of the pack, through a U-shaped passage formed in the camera, and then into the pack again, and into, or into contact with, the rearmost second sheet, via a transfer opening, which is formed in the pack in line with the rearmost second sheet, and which also permits removal of an independent film unit from the pack. When the first sheet has been moved completely into a correct positional relationship with the second sheet, the first and second sheets are moved out together as a single film unit, via the pack transfer opening, and then into and through a suitable passage formed in the camera, while being simultaneously processed. Time sequence control of this series of actions is suitably effected by various cam means acting on the various elements for effecting the actions. In this embodiment of the invention economy of parts and space is achieved since the same elements are employed both for shifting an exposed first sheet into association with a corresponding second sheet, and for moving an assembled film unit from the pack and out of the camera.
In a further embodiment of the invention, exposed first sheets are moved into association with second sheets by leaders provided in the pack as described earlier, but the entire action is controlled electronically, there being provided means by which clutches or similar elements supplying drive to the various shift and transfer means are actuated in a timed sequence subsequent to actuation of the camera shutter means to take a photograph.
It is to be noted that according to the invention, the photosensitive layer for formation of a negative image in a semi-film unit may, in effect, be located in front of or behind the film unit positive image layer, depending on the combination of first sheet construction and second sheet construction, whereby different types of film unit and different types of camera, for example, including or not including a mirror or mirrors in the optical system thereof, may be employed in accordance with different requirements. Also, loading or temporary unloading of film units is easy, since film units may be provided in a pack which, as far as the photographer is concerned, is merely a unitary block which may be simply inserted into or removed from a camera, without fine adjustments or fastidious attachment or fitting of small parts being necessary. Further, with a camera according to the invention, whatever the mode of first sheet transfer to a second sheet, or of removal of a single film unit, the only action required of a photographer in taking a photograph is to aim the camera and actuate the shutter button.